In order to improve the mass transfer characteristics, a coalescene-dispersion sieve plate was designed. Mass transfer experiments wer carried out in a coalescence-dispersion pulsed sieve extraction (PSE) column of 150 mm in diameter with a working system of 30% TBP (in kerosene)-nitric acid-water. Mass transfer direction was from the continuous phase to the dispersed phase,, namely form the aqueous phase to the organci phase. The mass transfer characteristics were evaluated by a dynamic tracer method. Three parameters, the 'true' height of the tranfer unit, the height of the dispersion unit and the apparent height ot the transfer unit, were estimated from the dynamic response curve. Compared woth that in a standard PSE column, the mass transfer formance in the coalescence-dispersion PSE column was greatly improved.